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S Tsukamoto

Publications and source records attributed to S Tsukamoto.

162 records · Page 9Linked to original sources
PubMed1975

alpha-Chymotryptic hydrolysis of derivatives of the specific substrates with substituents in the nucleus.

Steady state kinetic studies of alpha-chymotrypsin [EC 3.4.21.1]-catalyzed hydrolysis of nucleus-substituted derivatives of the specific substrates were made at pH 6.5 and 7.8. Ac-Trp(NCps)-OMe was hydrolyzed more readily than Ac-Trp-OMe owing to its smaller Km value. The kcat values of Ac-Trp(CHO)-OMe and Ac-Tyr(3-no2)-ome were higher than those of the corresponding unmodified substrates, suggesting that derivatives with a substituent as large as a formyl or nitro group at the epsilon-position are stereochemically favorable to the catalytic process. Derivatives of Ac-Phe-OMe with a chain of four atoms at the 3 or 4-position of the phenyl nucleus and 2,3-dihydropyrrolo[2,3-b]indoles derived from Ac-Trp-OMe were not hydrolyzed at all.

Chymotrypsin↗
PubMedDate not supplied

Clinical significance of the Rb expression in adenocarcinoma of the lung.

BACKGROUND: Altered retinoblastoma gene expression has been found in various types of cancers including non-small cell lung cancer (NSCLC) and some reports have shown it also to be associated with a poor clinical prognosis in NSCLC. MATERIALS AND METHODS: We evaluated the expression of Rb protein by immunohistochemistry in 90 patients with lung adenocarcinoma who underwent surgical resection and determined its prognostic significance. Also, the expression of p27 by immunohistochemistry and the mutations of the p53 gene by PCR-SSCP were evaluated. RESULTS: Fifty-one out of 90 tumors (56.7%) had reduced expression of the Rb gene. There were no statistical differences between the Rb expression level and clinicopathological status. There was no correlation between the Rb expression level and the p53 mutations or the p27 expression level. The 5-year survival rate in the normal group was 55.1%, which was poorer than that of 73.0% in the reduced group, but showed no statistical difference (p=0.0981). In patients with a reduced Rb-expression, the survival rate of the p53 mutation group tended to show a poorer prognosis than that of the p53 normal group (p=0.0880). In addition, the survival rate of the negative p27 expression group tended to show a poorer prognosis than that of the positive p27 expression group (p=0.0537). CONCLUSIONS: The Rb expression status was not significant as an individual factor for evaluating the prognosis in adenocarcinoma of the lung. Analyses of the accumulation of genetic alteration are necessary to identify the subset of patients with a poor prognosis.

Adenocarcinoma↗
PubMedDate not supplied

Second primary cancers after resection of lung adenocarcinoma with ras gene mutation.

BACKGROUND: Ras gene mutations are associated with a poor prognosis in patients with adenocarcinoma of the lung. However, the association between cases with ras gene mutation and an occurrence of second primary cancer is unknown. MATERIALS AND METHODS: We examined 89 adenocarcinoma of the lung obtained from patients treated by curative resection, and four second primary cancers, for mutation at codons 12, 13, and 61 of three ras oncogenes using polymerase chain reaction and oligonucleotide hybridization techniques. RESULTS: Ras gene mutations were detected in 13 cases. Six patients died from recurrent disease within 3 years. Of the seven patients who survived over 5 years, three patients demonstrated a metachronous second primary cancer after the operation for lung cancer, and one patient had synchronous laryngeal cancer. Two of the cases with second primary cancer demonstrated the ras gene mutation. One had the same mutation as that of the primary lung cancer, and the other had a different mutation from the first lung cancer. CONCLUSION: Ras gene mutations play an important role in tumor progression of lung adenocarcinoma and also might have an role in the carcinogenesis in respiratory tract cancer.

Adenocarcinoma↗